gcc/config/i386/linux.h

   1 /* Definitions for Intel 386 running Linux-based GNU systems with ELF format.
   2    Copyright (C) 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002
   3    Free Software Foundation, Inc.
   4    Contributed by Eric Youngdale.
   5    Modified for stabs-in-ELF by H.J. Lu.
   6
   7 This file is part of GNU CC.
   8
   9 GNU CC is free software; you can redistribute it and/or modify
  10 it under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 2, or (at your option)
  12 any later version.
  13
  14 GNU CC is distributed in the hope that it will be useful,
  15 but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 GNU General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GNU CC; see the file COPYING.  If not, write to
  21 the Free Software Foundation, 59 Temple Place - Suite 330,
  22 Boston, MA 02111-1307, USA.  */
  23
  24 #define LINUX_DEFAULT_ELF
  25
  26 /* Output at beginning of assembler file.  */
  27 /* The .file command should always begin the output.  */
  28 #undef ASM_FILE_START
  29 #define ASM_FILE_START(FILE)                                            \
  30   do {                                                                  \
  31         output_file_directive (FILE, main_input_filename);              \
  32         if (ix86_asm_dialect == ASM_INTEL)                              \
  33           fputs ("\t.intel_syntax\n", FILE);                            \
  34   } while (0)
  35
  36 #undef TARGET_VERSION
  37 #define TARGET_VERSION fprintf (stderr, " (i386 Linux/ELF)");
  38
  39 /* The svr4 ABI for the i386 says that records and unions are returned
  40    in memory.  */
  41 #undef DEFAULT_PCC_STRUCT_RETURN
  42 #define DEFAULT_PCC_STRUCT_RETURN 1
  43
  44 #undef ASM_COMMENT_START
  45 #define ASM_COMMENT_START "#"
  46
  47 #undef DBX_REGISTER_NUMBER
  48 #define DBX_REGISTER_NUMBER(n) \
  49   (TARGET_64BIT ? dbx64_register_map[n] : svr4_dbx_register_map[n])
  50
  51 /* Output assembler code to FILE to call the profiler.
  52    To the best of my knowledge, no Linux libc has required the label
  53    argument to mcount.  */
  54
  55 #define NO_PROFILE_COUNTERS
  56
  57 #undef FUNCTION_PROFILER
  58 #define FUNCTION_PROFILER(FILE, LABELNO)  \
  59 {                                                                       \
  60   if (flag_pic)                                                         \
  61     fprintf (FILE, "\tcall\t*mcount@GOT(%%ebx)\n");                     \
  62   else                                                                  \
  63     fprintf (FILE, "\tcall\tmcount\n");                                 \
  64 }
  65
  66 /* True if it is possible to profile code that does not have a frame
  67    pointer.
  68
  69    The GLIBC version of mcount for the x86 assumes that there is a
  70    frame, so we cannot allow profiling without a frame pointer.  */
  71
  72 #undef TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER
  73 #define TARGET_ALLOWS_PROFILING_WITHOUT_FRAME_POINTER false
  74
  75 #undef SIZE_TYPE
  76 #define SIZE_TYPE "unsigned int"
  77
  78 #undef PTRDIFF_TYPE
  79 #define PTRDIFF_TYPE "int"
  80
  81 #undef WCHAR_TYPE
  82 #define WCHAR_TYPE "long int"
  83
  84 #undef WCHAR_TYPE_SIZE
  85 #define WCHAR_TYPE_SIZE BITS_PER_WORD
  86
  87 #undef CPP_PREDEFINES
  88 #define CPP_PREDEFINES "-D__ELF__ -Dunix -Dlinux -Asystem=posix"
  89
  90 #undef CPP_SPEC
  91 #ifdef USE_GNULIBC_1
  92 #define CPP_SPEC "%(cpp_cpu) %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE}"
  93 #else
  94 #define CPP_SPEC "%(cpp_cpu) %{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"
  95 #endif
  96
  97 #undef CC1_SPEC
  98 #define CC1_SPEC "%(cc1_cpu) %{profile:-p}"
  99
 100 /* Provide a LINK_SPEC appropriate for Linux.  Here we provide support
 101    for the special GCC options -static and -shared, which allow us to
 102    link things in one of these three modes by applying the appropriate
 103    combinations of options at link-time. We like to support here for
 104    as many of the other GNU linker options as possible. But I don't
 105    have the time to search for those flags. I am sure how to add
 106    support for -soname shared_object_name. H.J.
 107
 108    I took out %{v:%{!V:-V}}. It is too much :-(. They can use
 109    -Wl,-V.
 110
 111    When the -shared link option is used a final link is not being
 112    done.  */
 113
 114 /* If ELF is the default format, we should not use /lib/elf.  */
 115
 116 #undef  LINK_SPEC
 117 #ifdef USE_GNULIBC_1
 118 #ifndef LINUX_DEFAULT_ELF
 119 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 120   %{!shared: \
 121     %{!ibcs: \
 122       %{!static: \
 123         %{rdynamic:-export-dynamic} \
 124         %{!dynamic-linker:-dynamic-linker /lib/elf/ld-linux.so.1} \
 125         %{!rpath:-rpath /lib/elf/}} %{static:-static}}}"
 126 #else
 127 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 128   %{!shared: \
 129     %{!ibcs: \
 130       %{!static: \
 131         %{rdynamic:-export-dynamic} \
 132         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.1}} \
 133         %{static:-static}}}"
 134 #endif
 135 #else
 136 #define LINK_SPEC "-m elf_i386 %{shared:-shared} \
 137   %{!shared: \
 138     %{!ibcs: \
 139       %{!static: \
 140         %{rdynamic:-export-dynamic} \
 141         %{!dynamic-linker:-dynamic-linker /lib/ld-linux.so.2}} \
 142         %{static:-static}}}"
 143 #endif
 144
 145 /* A C statement (sans semicolon) to output to the stdio stream
 146    FILE the assembler definition of uninitialized global DECL named
 147    NAME whose size is SIZE bytes and alignment is ALIGN bytes.
 148    Try to use asm_output_aligned_bss to implement this macro.  */
 149
 150 #define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
 151   asm_output_aligned_bss (FILE, DECL, NAME, SIZE, ALIGN)
 152
 153 /* A C statement to output to the stdio stream FILE an assembler
 154    command to advance the location counter to a multiple of 1<<LOG
 155    bytes if it is within MAX_SKIP bytes.
 156
 157    This is used to align code labels according to Intel recommendations.  */
 158
 159 #ifdef HAVE_GAS_MAX_SKIP_P2ALIGN
 160 #define ASM_OUTPUT_MAX_SKIP_ALIGN(FILE,LOG,MAX_SKIP)                    \
 161   do {                                                                  \
 162     if ((LOG) != 0) {                                                   \
 163       if ((MAX_SKIP) == 0) fprintf ((FILE), "\t.p2align %d\n", (LOG));  \
 164       else fprintf ((FILE), "\t.p2align %d,,%d\n", (LOG), (MAX_SKIP));  \
 165     }                                                                   \
 166   } while (0)
 167 #endif
 168
 169 #if defined(__PIC__) && defined (USE_GNULIBC_1)
 170 /* This is a kludge. The i386 GNU/Linux dynamic linker needs ___brk_addr,
 171    __environ and atexit.  We have to make sure they are in the .dynsym
 172    section.  We do this by forcing the assembler to create undefined
 173    references to these symbols in the object file.  */
 174 #undef CRT_CALL_STATIC_FUNCTION
 175 #define CRT_CALL_STATIC_FUNCTION(SECTION_OP, FUNC)      \
 176    asm (SECTION_OP "\n\t"                               \
 177         "call " USER_LABEL_PREFIX #FUNC "\n"            \
 178         TEXT_SECTION_ASM_OP "\n\t"                      \
 179         ".extern ___brk_addr\n\t"                       \
 180         ".type ___brk_addr,@object\n\t"                 \
 181         ".extern __environ\n\t"                         \
 182         ".type __environ,@object\n\t"                   \
 183         ".extern atexit\n\t"                            \
 184         ".type atexit,@function");
 185 #endif
 186
 187 /* Handle special EH pointer encodings.  Absolute, pc-relative, and
 188    indirect are handled automatically.  */
 189 #define ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX(FILE, ENCODING, SIZE, ADDR, DONE) \
 190   do {                                                                  \
 191     if ((SIZE) == 4 && ((ENCODING) & 0x70) == DW_EH_PE_datarel)         \
 192       {                                                                 \
 193         fputs (ASM_LONG, FILE);                 \
 194         assemble_name (FILE, XSTR (ADDR, 0));                           \
 195         fputs (((ENCODING) & DW_EH_PE_indirect ? "@GOT" : "@GOTOFF"), FILE); \
 196         goto DONE;                                                      \
 197       }                                                                 \
 198   } while (0)
 199
 200 /* Used by crtstuff.c to initialize the base of data-relative relocations.
 201    These are GOT relative on x86, so return the pic register.  */
 202 #ifdef __PIC__
 203 #define CRT_GET_RFIB_DATA(BASE)                 \
 204   {                                             \
 205     register void *ebx_ __asm__("ebx");         \
 206     BASE = ebx_;                                \
 207   }
 208 #else
 209 #define CRT_GET_RFIB_DATA(BASE)                                         \
 210   __asm__ ("call\t.LPR%=\n"                                             \
 211            ".LPR%=:\n\t"                                                \
 212            "popl\t%0\n\t"                                               \
 213            /* Due to a GAS bug, this cannot use EAX.  That encodes      \
 214               smaller than the traditional EBX, which results in the    \
 215               offset being off by one.  */                              \
 216            "addl\t$_GLOBAL_OFFSET_TABLE_+[.-.LPR%=],%0"                 \
 217            : "=d"(BASE))
 218 #endif
 219
 220 /* Do code reading to identify a signal frame, and set the frame
 221    state data appropriately.  See unwind-dw2.c for the structs.  */
 222
 223 #ifdef IN_LIBGCC2
 224 #include <signal.h>
 225 #include <sys/ucontext.h>
 226 #endif
 227
 228 #define MD_FALLBACK_FRAME_STATE_FOR(CONTEXT, FS, SUCCESS)               \
 229   do {                                                                  \
 230     unsigned char *pc_ = (CONTEXT)->ra;                                 \
 231     struct sigcontext *sc_;                                             \
 232     long new_cfa_;                                                      \
 233                                                                         \
 234     /* popl %eax ; movl $__NR_sigreturn,%eax ; int $0x80  */            \
 235     if (*(unsigned short *)(pc_+0) == 0xb858                            \
 236         && *(unsigned int *)(pc_+2) == 119                              \
 237         && *(unsigned short *)(pc_+6) == 0x80cd)                        \
 238       sc_ = (CONTEXT)->cfa + 4;                                         \
 239     /* movl $__NR_rt_sigreturn,%eax ; int $0x80  */                     \
 240     else if (*(unsigned char *)(pc_+0) == 0xb8                          \
 241              && *(unsigned int *)(pc_+1) == 173                         \
 242              && *(unsigned short *)(pc_+5) == 0x80cd)                   \
 243       {                                                                 \
 244         struct rt_sigframe {                                            \
 245           int sig;                                                      \
 246           struct siginfo *pinfo;                                        \
 247           void *puc;                                                    \
 248           struct siginfo info;                                          \
 249           struct ucontext uc;                                           \
 250         } *rt_ = (CONTEXT)->cfa;                                        \
 251         sc_ = (struct sigcontext *) &rt_->uc.uc_mcontext;               \
 252       }                                                                 \
 253     else                                                                \
 254       break;                                                            \
 255                                                                         \
 256     new_cfa_ = sc_->esp;                                                \
 257     (FS)->cfa_how = CFA_REG_OFFSET;                                     \
 258     (FS)->cfa_reg = 4;                                                  \
 259     (FS)->cfa_offset = new_cfa_ - (long) (CONTEXT)->cfa;                \
 260                                                                         \
 261     /* The SVR4 register numbering macros aren't usable in libgcc.  */  \
 262     (FS)->regs.reg[0].how = REG_SAVED_OFFSET;                           \
 263     (FS)->regs.reg[0].loc.offset = (long)&sc_->eax - new_cfa_;          \
 264     (FS)->regs.reg[3].how = REG_SAVED_OFFSET;                           \
 265     (FS)->regs.reg[3].loc.offset = (long)&sc_->ebx - new_cfa_;          \
 266     (FS)->regs.reg[1].how = REG_SAVED_OFFSET;                           \
 267     (FS)->regs.reg[1].loc.offset = (long)&sc_->ecx - new_cfa_;          \
 268     (FS)->regs.reg[2].how = REG_SAVED_OFFSET;                           \
 269     (FS)->regs.reg[2].loc.offset = (long)&sc_->edx - new_cfa_;          \
 270     (FS)->regs.reg[6].how = REG_SAVED_OFFSET;                           \
 271     (FS)->regs.reg[6].loc.offset = (long)&sc_->esi - new_cfa_;          \
 272     (FS)->regs.reg[7].how = REG_SAVED_OFFSET;                           \
 273     (FS)->regs.reg[7].loc.offset = (long)&sc_->edi - new_cfa_;          \
 274     (FS)->regs.reg[5].how = REG_SAVED_OFFSET;                           \
 275     (FS)->regs.reg[5].loc.offset = (long)&sc_->ebp - new_cfa_;          \
 276     (FS)->regs.reg[8].how = REG_SAVED_OFFSET;                           \
 277     (FS)->regs.reg[8].loc.offset = (long)&sc_->eip - new_cfa_;          \
 278     (FS)->retaddr_column = 8;                                           \
 279     goto SUCCESS;                                                       \
 280   } while (0)